Mechanism for converting rotary motion to reciprocatory motion



gamma I March 21, 1950 MECHANISM FOR CNVERTING ROTARY MOTION To RECIPROCATORY MOTION 2 Sheets-Sheet 1' Filed April 1, 1947 Q m. 2 /0 N PM mm u an m E cm W J 4 m n n M n u 2. W n m M n m W 2 M. OSCHWALD MECHANISM FOR CONVERTING ROTARY MOTION TO RECIPROCATORY MOTION 2 Sheets-Sheet 2 Filed April 1, 1947 atented Mar. 21, 1950 MECHANISM FOR CONVERTING ROTAItY MOTION TO RECIPROCATORY MOTION Max Oschwald, Zuchwil, Switzerland, assignor T to Scintilla A-G., Solothurn, Switzerland, a cornotation of Switzerland Application April 1, 1947, Serial No. 738,660 In Switzerland November 24, 1944 Secion 1, Public Law 690, August 8, 1946 Patent expires November 24, 1964 2 Claims.

This .invention relates to motor-driven tools designated to be moved by hand, and more especially to motor-driven reciprocating hand tools such as saws, cutters, files and the like, wherein the handle of the tool is formed by the motor housing.

It is an object of the invention to provide a light and handy tool permitting to operate on work pieces that are too bulky to be worked on a machine tool, such as large plywood panels or lumber boards, or which enables work to be performed in positions which are inaccessible for ordinary hand tools.

A further object of the invention is to provide a mechanism for converting the rotary motion of a motor into rectilinear reciprocatory motion, while eliminating the vibrations generated by its masses while they reciprocate at frequencies of at least 3000 power cycles per minute.

In order that the invention may be more readily understood, I will now describe two embodiments thereof which are illustrated diagrammatically by way of example in the accompanying drawings, in which:

Fig. 1 is a perspective view of the tool as a whole; while Fig. 2 is an axial sectional view,.

drawn to a larger scale, of a first embodiment of the invention.

Fig. 3 being a front view wherein the cover with the reciprocating tool is removed to show the disposition of parts of the mechanism and some of the counterbalance elements.

Fig. 4 is a part sectional view of a second embodiment.

Referring first to Figs. 1 to 3, the mechanism here illustrated shows a motor shaft fitted with a pinion which drives two gear wheels of equal size positioned in substantially the same plane and on a common diameter line. One gear wheel actuates a reciprocating device, which in turn reciprocates a tool, while the other gear wheel actuates a reciprocating device, which in turn reciprocates a counterbalance, the respective mo- 7 tions of both being such that the reciprocation of one of said devices is opposed to that of the other, thereby producing a uniform and vibrationless action of the tool.

The handle of the tool is formed by the housing I of an electric motor having a front bearing plate 2 through which projects the motor shaft 3, which is fitted with a pinion 4. On the front bearing plate 2 two gear wheels 5 and 6 are rotatably mounted on their fixed journals 5a and 6a respectively. Both of these gear wheels have an equal number of teeth. They are permanently 2 in mesh with the pinion 4 on the motor shaft and are driven by it when the motor is operated. On one of the gear wheels 5 a crank pin 1 is eccentrically mounted. This crank pin I engages a slot 8 in a carrier 9, which is fixed to a reciprocatable tool arm E0 to which the tool H is secured.

The reciprocatable tool arm Ill is mounted in a guide l4 which is supported in the casing l3 of the gear-box l2 and has at one end a head 15 adapted to grip the tool I l which is secured therein by a fastening screw it. The tool H, in the present case a saw, is Supported by means of an adjustable guide I! with a counter-pressure roller I 8 bearing against the tool. It is obvious that the saw may be replaced by a cutter or by a file without departing from the scope of the invention.

On one side of the gear-box l2 a supporting plate or pedestal base I9 is arranged parallel to the motor axis. This plate is slotted lengthwise and through the slot the reciprocating tool projects at right angles to the base l9 which permits of the latter resting on the work and being used as in Fig. 1. On the opposite side of the gearbox a base member 28 may be provided by which may support the mechanism, as for example, in a vise 29. When so mounted, the reciprocating tool is directed vertically upwards and the pedestal base I 9 serves as a work stage. The pedestal base may be adjustably mounted on the gearbox l2 and may be movable by means of joints I (not shown), thus permitting the work to be presented to the tool at any angle.

Diametrically opposed to the aforementioned gear wheel 5 is the second gear wheel 6 mounted on its journal 6a. The latter gearwheel 6 is fitted with a crank pin 20 which engages with a transverse slot 2i in the counter-balance weight 22.

This weight has on its other side, at right angles to the transverse slot, two guide slots 23 fitting guides 24 which are mounted orformed in the interior of the gear-box I2 so as to keep the balance weight in rectilinear direction.

When, by means of the motor, the pinion 4 on its shaft and the gear wheels 5 and 6 engaging scribed above, reciprocation of the tool arm I and of the balance weight 22 may be accomplished by rods connected to crank pins on the gear wheels I and 8 by spigots fixed to the reciprocating parts and riding in eccentric grooves out into the face of the gear wheels.

For greasing the moving parts in the gearbox i2, an aperture 25 is provided therein with a copper plate 21 rockably fastened to the gear box by a screw 28.

The embodiment shown in Fig. 4 provides for the motor being able to serve other purposes besides the one described, for instance, to drive a small compressor (not shown) or'some other suitable implement secured to its front end. In order to facilitate conversion, an intermediate bearing plate 31 supporting the gearing components, and a disengaging clutch 30 on the motor shaft between the intermediate plate 3i and the front bearing plate 2, may be incorporated in the mechanism. The said intermediate bearing plate 3i may be fastened to the motor housing by means of screws or in some other manner.

I wish it to be understood that I do not desire to be limited to the details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:

1. A mechanism for converting high speed rotary motion of a prime mover into high speed reciprocating motion of a driven member and a counter-balancing mass comprising, a first power transmitting member mounted for rotation about an axis parallel to said prime mover for driving said driven member, a second power transmitting member mounted for rotation about a second axis parallel to said prime mover for driving said mass, said power transmitting members being positioned in substantially the same plane and spaced from one another, means positioned between said power transmitting members for driving said power transmitting members from said prime mover, guiding means for said driven member positioned in proximity to said second power transmitting member and spaced therefrom, said driven member being slidably supported by said guiding means for reciprocating movement in a plane substantially parallel to the plane of said power transmitting members and extending from a point in the proximity of and opposite to said second power transmitting member to a point in proximity to said first power transmitting member, means supporting said mass for reciprocating movement intermediate said driven member and said second power transmitting means, means on each of said driven member and said counter-balancing mass extending transversely of said axes and of the direction of movement of said mass and said driven member, and a crank member on each of said power transmitting members operatively engaging said transversely extending means so as to move each of said counter-balancing mass and driven member simultaneously.

2. A mechanism for converting high speed rotary motion of a prime mover into high speed reciprocating motion of a driven member and a counter-balancing mass comprising, a first power transmitting member mounted for rotation about an axis parallel to said prime mover for driving said driven member, a second power transmitting member mounted for rotation about a second axis parallel to said prime mover for driving said mass, said power transmitting members being positioned in substantially the same plane and spaced from one another, means positioned between said power transmitting members for driving said power transmitting members from said prime mover, guiding means for said driven member, said guiding means including a sleeve opposite to and spaced from said second. power trans mitting member, said driven member being slidably supported in said sleeve for reciprocating movement in a plane substantially parallel to the plane of said power transmitting members and extending from within said sleeve to a point in proximity to said first power transmitting member, means supporting said mass for reciprocating movement intermediate said driven member and said second power transmitting means, means on each of said driven member and said counter-balancing mass extending transversely of said axes and of the direction of movement of said mass and said driven member, and a crank member on each of said power transmitting members operatively engaging said transversely extending means so as to move each of said counter-balancing mass and driven member simultaneously.

MAX OSCHWALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 200,306 Irick Feb. 12, 1878 I 702,371 Meyer June 10, 1902 812,507 Ludewlck Feb. 13, 1906 841,325 King Jan. 15, 1907 1,126,899 Specht et a1. Feb. 2, 1915 1,382,821 Coates June 28, 1921 1,542,127 Hastings June 16, 1925 1,620,374 Maloney Mar. 8, 1927 1,643,721 Meyer Sept. 27, 1927 1,648,008 Selby et a1 Nov. 8, 1927 1,661,217 Farrell Mar. 6, 1928 I 1,700,114 Thompson Jan. 22, 1929 1,700,115 Thompson Jan. 22, 1929 1,789,804 Broillet Jan. 20, 1931 1,868,507 Ros July 26, 1932 2,138,862 Johnston Dec. 6, 1938 2,281,641 Toop May 5, 1942 2,282,728 Kern May 12, 1942 2,328,613 Burleigh Sept. 7, 1943 2,345,383 Curtis Mar. 28, 1944 2,428,924 Albertson Oct. 14, 1947 

